Preheat your oven to 350°F (175°C). Gather all your ingredients and equipment.

Spray the 9" x 13" baking dish generously with non-stick spray.

In a mixing bowl, whisk together the flour, baking powder, and salt.

In a large mixing bowl, beat together the butter, brown sugar, eggs, and vanilla extract until smooth and creamy.

Gradually add the flour mixture to the wet ingredients, mixing until well combined.

Pour the batter into the prepared baking dish, smoothing it out evenly.

In a small bowl, combine the granulated sugar with ground cinnamon.

Sprinkle the cinnamon-sugar mixture evenly over the batter.

Bake in the preheated oven for 25-30 minutes until a toothpick inserted comes out clean.

Let the bars cool in the pan for at least 15 minutes before cutting into squares.